Logic Masters Deutschland e.V.

Here's just a puzzle I quickly put together. I think this should be a fairly approachable one although there could be one or two trickier deductions. Probably still 2 stars overall I would say but I have been wrong before!
I hope you enjoy, feedback welcome!

• Normal sudoku rules apply: place the digits 1-9 once each in every row, column and 3x3 box.
• 3-whisper region sum lines: box borders divide blue lines into segments, each of which sums to the same total. Different lines can have different sums. Additionally, adjacent digits on these lines have a difference of at least 3.
• Quadruples: digits in a circle must appear in one of the surrounding cells.